// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_HTTP_HTTP_TRANSACTION_H_
#define NET_HTTP_HTTP_TRANSACTION_H_

#include <stdint.h>

#include "net/base/completion_callback.h"
#include "net/base/load_states.h"
#include "net/base/net_error_details.h"
#include "net/base/net_export.h"
#include "net/base/request_priority.h"
#include "net/base/upload_progress.h"
#include "net/socket/connection_attempts.h"
#include "net/websockets/websocket_handshake_stream_base.h"

namespace net {

class AuthCredentials;
class BoundNetLog;
class HttpRequestHeaders;
struct HttpRequestInfo;
class HttpResponseInfo;
class IOBuffer;
struct LoadTimingInfo;
class ProxyInfo;
class QuicServerInfo;
class SSLPrivateKey;
class X509Certificate;

// Represents a single HTTP transaction (i.e., a single request/response pair).
// HTTP redirects are not followed and authentication challenges are not
// answered.  Cookies are assumed to be managed by the caller.
class NET_EXPORT_PRIVATE HttpTransaction {
public:
    // If |*defer| is set to true, the transaction will wait until
    // ResumeNetworkStart is called before establishing a connection.
    typedef base::Callback<void(bool* defer)> BeforeNetworkStartCallback;

    // Provides an opportunity to add additional request headers. Called after
    // a connection is established and before the request headers are sent.
    // |proxy_info| contains information about any proxies being used, and
    // additional headers may be added to |request_headers|.
    typedef base::Callback<void(const ProxyInfo& proxy_info,
        HttpRequestHeaders* request_headers)>
        BeforeHeadersSentCallback;

    // Stops any pending IO and destroys the transaction object.
    virtual ~HttpTransaction() { }

    // Starts the HTTP transaction (i.e., sends the HTTP request).
    //
    // Returns OK if the transaction could be started synchronously, which means
    // that the request was served from the cache.  ERR_IO_PENDING is returned to
    // indicate that the CompletionCallback will be notified once response info is
    // available or if an IO error occurs.  Any other return value indicates that
    // the transaction could not be started.
    //
    // Regardless of the return value, the caller is expected to keep the
    // request_info object alive until Destroy is called on the transaction.
    //
    // NOTE: The transaction is not responsible for deleting the callback object.
    //
    // Profiling information for the request is saved to |net_log| if non-NULL.
    virtual int Start(const HttpRequestInfo* request_info,
        const CompletionCallback& callback,
        const BoundNetLog& net_log)
        = 0;

    // Restarts the HTTP transaction, ignoring the last error.  This call can
    // only be made after a call to Start (or RestartIgnoringLastError) failed.
    // Once Read has been called, this method cannot be called.  This method is
    // used, for example, to continue past various SSL related errors.
    //
    // Not all errors can be ignored using this method.  See error code
    // descriptions for details about errors that can be ignored.
    //
    // NOTE: The transaction is not responsible for deleting the callback object.
    //
    virtual int RestartIgnoringLastError(const CompletionCallback& callback) = 0;

    // Restarts the HTTP transaction with a client certificate.
    virtual int RestartWithCertificate(X509Certificate* client_cert,
        SSLPrivateKey* client_private_key,
        const CompletionCallback& callback)
        = 0;

    // Restarts the HTTP transaction with authentication credentials.
    virtual int RestartWithAuth(const AuthCredentials& credentials,
        const CompletionCallback& callback)
        = 0;

    // Returns true if auth is ready to be continued. Callers should check
    // this value anytime Start() completes: if it is true, the transaction
    // can be resumed with RestartWithAuth(L"", L"", callback) to resume
    // the automatic auth exchange. This notification gives the caller a
    // chance to process the response headers from all of the intermediate
    // restarts needed for authentication.
    virtual bool IsReadyToRestartForAuth() = 0;

    // Once response info is available for the transaction, response data may be
    // read by calling this method.
    //
    // Response data is copied into the given buffer and the number of bytes
    // copied is returned.  ERR_IO_PENDING is returned if response data is not
    // yet available.  The CompletionCallback is notified when the data copy
    // completes, and it is passed the number of bytes that were successfully
    // copied.  Or, if a read error occurs, the CompletionCallback is notified of
    // the error.  Any other negative return value indicates that the transaction
    // could not be read.
    //
    // NOTE: The transaction is not responsible for deleting the callback object.
    // If the operation is not completed immediately, the transaction must acquire
    // a reference to the provided buffer.
    //
    virtual int Read(IOBuffer* buf, int buf_len,
        const CompletionCallback& callback)
        = 0;

    // Stops further caching of this request by the HTTP cache, if there is any.
    virtual void StopCaching() = 0;

    // Gets the full request headers sent to the server.  This is guaranteed to
    // work only if Start returns success and the underlying transaction supports
    // it.  (Right now, this is only network transactions, not cache ones.)
    //
    // Returns true and overwrites headers if it can get the request headers;
    // otherwise, returns false and does not modify headers.
    virtual bool GetFullRequestHeaders(HttpRequestHeaders* headers) const = 0;

    // Get the number of bytes received from network.
    virtual int64_t GetTotalReceivedBytes() const = 0;

    // Get the number of bytes sent over the network.
    virtual int64_t GetTotalSentBytes() const = 0;

    // Called to tell the transaction that we have successfully reached the end
    // of the stream. This is equivalent to performing an extra Read() at the end
    // that should return 0 bytes. This method should not be called if the
    // transaction is busy processing a previous operation (like a pending Read).
    //
    // DoneReading may also be called before the first Read() to notify that the
    // entire response body is to be ignored (e.g., in a redirect).
    virtual void DoneReading() = 0;

    // Returns the response info for this transaction. Must not be called until
    // |Start| completes.
    virtual const HttpResponseInfo* GetResponseInfo() const = 0;

    // Returns the load state for this transaction.
    virtual LoadState GetLoadState() const = 0;

    // Returns the upload progress in bytes.  If there is no upload data,
    // zero will be returned.  This does not include the request headers.
    virtual UploadProgress GetUploadProgress() const = 0;

    // SetQuicServerInfo sets a object which reads and writes public information
    // about a QUIC server.
    virtual void SetQuicServerInfo(QuicServerInfo* quic_server_info) = 0;

    // Populates all of load timing, except for request start times and receive
    // headers time.
    // |load_timing_info| must have all null times when called.  Returns false and
    // does not modify |load_timing_info| if there's no timing information to
    // provide.
    virtual bool GetLoadTimingInfo(LoadTimingInfo* load_timing_info) const = 0;

    // Gets the remote endpoint of the socket that the transaction's underlying
    // stream is using or did use, if any. Returns true and fills in |endpoint|
    // if it is available; returns false and leaves |endpoint| unchanged if it is
    // unavailable.
    virtual bool GetRemoteEndpoint(IPEndPoint* endpoint) const = 0;

    // Populates network error details for this transaction.
    virtual void PopulateNetErrorDetails(NetErrorDetails* details) const = 0;

    // Called when the priority of the parent job changes.
    virtual void SetPriority(RequestPriority priority) = 0;

    // Set the WebSocketHandshakeStreamBase::CreateHelper to be used for the
    // request.  Only relevant to WebSocket transactions. Must be called before
    // Start(). Ownership of |create_helper| remains with the caller.
    virtual void SetWebSocketHandshakeStreamCreateHelper(
        WebSocketHandshakeStreamBase::CreateHelper* create_helper)
        = 0;

    // Sets the callback to receive notification just before network use.
    virtual void SetBeforeNetworkStartCallback(
        const BeforeNetworkStartCallback& callback)
        = 0;

    // Sets the callback to receive notification just before request headers
    // are to be sent.
    virtual void SetBeforeHeadersSentCallback(
        const BeforeHeadersSentCallback& callback)
        = 0;

    // Resumes the transaction after being deferred.
    virtual int ResumeNetworkStart() = 0;

    virtual void GetConnectionAttempts(ConnectionAttempts* out) const = 0;
};

} // namespace net

#endif // NET_HTTP_HTTP_TRANSACTION_H_
